A gas turbine engine typically includes a fan section, a compressor section, a combustor section, and a turbine section. In general, during operation air is pressurized in the compressor section and is mixed with fuel and burned in the combustor section to generate hot combustion gases. The hot combustion gases flow through the turbine section, which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads. The compressor section may typically include low pressure and high pressure compressors, and the turbine section may typically include low pressure and high pressure turbines.
The combustor is typically coupled to an engine case of the gas turbine engine. The engine case may include a diffuser case, which circumscribes the compressor section. The diffuser case and fittings may be subjected to relatively high temperatures due to heat convectively transferred from the combustor to the diffuser case. Thermal loads in the diffuser case may cause thermal gradients that may stress, deform, fracture, and/or degrade portions of the diffuser case over time. A flange of the diffuser case may experience thermal gradients of at least 400° F. (204° C.) to 600° F. (315° C.). Stress and degradation caused by the thermal gradients may shorten the operational life of engine case components.